Descrizione del progetto
Un futuro molto promettente per i LED organici
I diodi a emissione luminosa (LED) hanno rivoluzionato le applicazioni nel campo dell’illuminazione, dei rilevamenti e delle comunicazioni, dai televisori alla segnaletica, fino alla biomedicina. C’è voluto però del tempo. Più di un secolo fa, gli scienziati scoprirono che applicando corrente ad un cristallo di carburo di silicio, questo emetteva una luce giallastra. I LED sono diventati commercialmente disponibili su larga scala negli anni ’70. Oggi, i cosiddetti LED organici (OLED), ovvero l’alternativa organica a pellicola sottile ai materiali semiconduttori, stanno guadagnando terreno. Tuttavia, nonostante i loro numerosi benefici rispetto ai LED tradizionali, presentano limiti notevoli in termini di luminosità. Inoltre, non possono essere utilizzati facilmente come mezzo laser a causa delle difficoltà tecniche inerenti al pompaggio, ovvero il processo attraverso cui viene fornita energia al mezzo per favorire l’eccitazione dei suoi elettroni. ’Il progetto ULTRA-LUX affronterà entrambe le problematiche al fine di realizzare il primo dispositivo emettitore di luce ultra luminoso a pellicola sottile, integrato da un laser d’iniezione a pellicola sottile.
Obiettivo
Thin-film light sources such as OLEDs are extremely valuable, as, in contrast to III-V crystalline LEDs, they can be precisely designed and dimensioned, as single components or in massive arrays, into any target application without the need of hetero-assembly. Unfortunately, their light power density remains about 300 times smaller than that of III-V LEDs. Also, none of today’s thin-film light sources could ever be brought to lasing by electrical pumping.
It is the objective of this project to break through the barriers that limit the brightness of thin-film light sources and to achieve lasing by electrical pumping (“injection lasing”) in such sources.
Our first target is to create a high-brightness (30W/cm2) thin-film light-emitting device. For the emission layer, we propose a perovskite semiconductor with controlled quantum-confinement features (wells or dots). It will be integrated into a novel light-emitting device, in which electron and hole injection are separately controlled by gates, such that a perfect charge balance is achieved up to the highest current densities.
Our next target is to create a thin-film injection laser. We present several innovative strategies to lower the lasing threshold. The emission layer of our light-emitting device will be shaped as a ring resonator with ultra-low optical losses. The gates will be patterned to spatially modulate the carrier injection in the emission layer, which will efficiently restrict the pumping to few selected modes. Further elaborations of cavity designs can lead to mode-locking. Combined with the efficiency of the quantum-confined perovskite emission layer in producing optical gain, these features will reduce the lasing threshold current density to below 100 A/cm2, within reach of our thin-film device.
These novel devices will serve numerous applications in the fields of sensing and ICT, by enabling massive optical interconnects, augmented reality displays, on-chip sensing and more.
Campo scientifico
Programma(i)
Argomento(i)
Meccanismo di finanziamento
ERC-ADG - Advanced GrantIstituzione ospitante
3001 Leuven
Belgio